WEDNESDAY, Nov. 3 (HealthDayNews) -- Common brands of oats are contaminated with gluten, according to a new finding that could be of concern to people with celiac disease who've been told the foods are safe to eat.

Still, the result is not enough to herald any definitive conclusions or changes in established practice, according to its author. "All you can basically say right now is that contamination concerns are indeed legitimate," said Tricia Thompson, who wrote a letter outlining the findings in the Nov. 4 issue of the New England Journal of Medicine.

"Patients need to be careful [not to just start] going out and pulling oats off the shelves, and they should be encouraged to contact oat millers directly and talk to them about their clean-out procedures," she added.

Gluten is the umbrella name for a group of proteins found in wheat, barley and rye. While oats do not appear to naturally contain gluten, they can become contaminated during harvesting, transporting, milling and processing.

In people with celiac disease, gluten triggers an autoimmune response that results in damage to the small intestine. Over time, that damage can cause the small intestine to lose its ability to absorb the nutrients found in food.

All celiac organizations in the United States currently advise against eating oats -- in addition to wheat, barley, and rye -- just to be on the safe side.

However, there is a small but increasing chorus suggesting that people with celiac disease can consume small amounts of uncontaminated oats, though this is not definitive. Scientific evidence currently leans toward the notion that "oats per se may not be toxic to celiac patients," said Tom Sullivan, president of the Celiac Sprue Association, which partially supported this research and which advocates a zero tolerance policy with respect to rye, barley, wheat and oats.

There has been previous research on whether pure oats (not commercial oats) could be consumed by people with celiac disease. "Over the years, Scandinavian countries and the U.K. basically have been allowing oats because a lot of these studies have shown that moderate amounts of uncontaminated oats were safe for most adults with celiac. That's the very careful language that was used," Thompson added.

For this study, Thompson had an independent laboratory test 12 containers of rolled or steel-cut oats representing four different lots of each of three brands. The three brands were Quaker, Country Choice (certified to be organic), and McCann's (processed in an oats-only facility).

Samples were considered gluten-free if they contained 20 parts per million (ppm) or less of gluten, which is in accordance with current Codex limits for naturally gluten-free food. Codex is a joint effort between the Food and Agriculture Organization of the United Nations and the World Health Organization and sets the standard of gluten content allowed in a food product labeled to be gluten-free. But even this limit isn't a final ruling and may change, Thompson warned.

Three of the 12 oat samples contained gluten levels of less than 20 ppm. The other nine had levels that ranged from 23 to 1,807 ppm. All three brands had at least two samples with levels above 20 ppm. Levels of gluten in McCann's products ranged from below the limit of detection to 725 ppm; in Country Choice, from below the limit of detection to 210 ppm; and in Quaker products from 338 to 1,807 ppm.

What does this all mean?

"It's basically a snapshot picture and so we have no idea if we tested 100 lots of each of these brands whether these results would hold," Thompson said.

Other factors are also at play. "The effect [of eating contaminated oats] will depend on whether the person is ingesting it on a daily basis or is it one container out of four," Thompson. "We don't know how much over what period of time is needed to cause damage, although you probably would not want to consume something that had 700 ppm of gluten on daily basis over time."

More guidance from the Codex Commission is needed before there can be ea universal endorsement of oats in this country, Thompson said. "We don't yet know what amount of gluten consumed on a daily basis is safe for most people with celiac disease, and right now, the draft revised standard of the Codex Commission says up to 20 ppm, but that's not a final statement. That number may be revised and it may be revised upwards," she continued.

For now, nothing much seems to have changed. "I think it's fair to say that there is little definitive information that should cause deviation from the standards of zero tolerance for wheat, rye, barley and oats," Sullivan said. "Right now the only known cure is the diet change."